Pressures available for transtracheal jet ventilation from anesthesia machines and wall-mounted oxygen flowmeters.

BACKGROUND

Oxygen supplies capable of supporting transtracheal jet ventilators can be lifesaving. There is not much information about which oxygen sources (readily available inside and outside operating rooms) have sufficient driving pressure for transtracheal jet ventilation.

METHODS

We measured driving pressures (upstream or residual oxygen pressure) in a specially designed jet ventilation test system with a 2.25-mm (14-gauge) i.v. catheter. High-pressure oxygen sources evaluated included wall-mounted (Puritan, Allied Health, Precision, and Datex-Ohmeda) and anesthesia machine auxiliary oxygen flowmeters and oxygen flush valves from anesthesia machines (Draeger Narkomed 2B, Narkomed 4, Datex-Ohmeda Excel, and Datex-Ohmeda Modulus).

RESULTS

All 4 types of wall-mounted oxygen flowmeters, opened past their highest scale settings (15 L/min), delivered sufficient working pressures (range, 103-282 kPa; 16-41 psi). Working pressures from auxiliary oxygen flowmeters mounted on Datex-Ohmeda machines were adequate to support jet ventilation (range, 189-248 kPa; 27-36 psi), whereas those on tested Draeger machines did not supply sufficient pressure for jet ventilation: Narkomed 2B, 14-28 kPa (2-4 psi); Narkomed 4, 24-28 kPa (3-4 psi). Working pressures delivered by oxygen flush valves on tested Draeger machines were adequate to support jet ventilation, ranging from 96 to 117 kPa (14-17 psi), whereas pressures generated by tested Datex-Ohmeda flush valves were not (ranging from 50 to 62 kPa, 7-9 psi).

CONCLUSION

Oxygen sources other than dedicated jet ventilator connectors to high-pressure pipeline oxygen may supply adequate working pressure, but each type of oxygen source needs testing to ensure that it supplies adequate working pressure.